My file is like this-

Pcol-patient
Mcol-Mutation



   Pcol       Mcol
    P1      M1,M2,M5,M6
    P2      M1,M2,M3,M5
    P3      M4,M5,M7,M6

I want to find all the combination of Mcol elements and their frequency( combinatinatons that present in how many patients) according to Pcol i,e patient.

Expected output-

Mcol        freq
M1,M2        2
M1,M5        2
M1,M6        1
M2,M5        2
M2,M6        1
M5,M6        2
M1,M3        1
M2,M3        1
M4,M5        1
M4,M7        1
M4,M6        1
M7,M6        1

I have tried this-

x <- read.csv("file.csv" ,header = TRUE, stringsAsFactors = FALSE)
xx <- do.call(rbind.data.frame, 
              lapply(x$Mcol, function(i){
                n <- sort(unlist(strsplit(i, ",")))
                t(combn(n, 2))
              }))

data.frame(table(paste(xx[, 1], xx[, 2], sep = ",")))

It doesn't give the expected output